Coupling devices are known and are commercially available in a standard embodiment, as disclosed, for example, in the specification for the American SAE-Standard J518, revised wording of June 1993.
The clamping screws, provided for the pressing of the pipe-end flange on the contacting face of the connecting part in the case of the known coupling device, extend through bores in two clamping jaws. These clamping jaws have each the shape of a half-ring. Each one surrounds one half of the periphery of the end flange found on the pipe. Each of these half-rings is supported on the surface of the flange opposite the end face. When the coupling device is in assembled state, the two half-rings form a closed flange ring, which encloses the end flange on the pipe. The bores for the clamping screws are arranged diametrically opposite one another in pairs in the four corner areas of this flange ring formed by the half-rings of the clamping jaws.
The known clamping devices, on account of the clamping jaws forming the exterior flange ring, are not only bulky, but on account of the number of structural parts required are expensive to manufacture. One particular drawback is in that the assembly process for the known coupling devices is difficult and time-consuming. To produce the screwing together during the assembly, it is necessary to lay out the end face of the flange adjacent to the pipe on the contact surface on the connecting part and simultaneously to hold the two clamping jaws on the end flange of the pipe engaging in such a position that the bores for the clamping screws are aligned with associated threaded bores in the connecting part. These processes can be executed by one single assembly person only with considerable difficulty.
With a coupling device as found in FR 668,578 A, for simplification of the assembly, the contacting surface of the connecting part is formed by the base of a recess surrounding its outlet. The end flange of the pipe can be received so that the border of the recess forms a secure fixing against displacement of the flange in radial direction. However, a ring or half-ring is likewise required to enclose the flange on the pipe.